Britain's economy grew by a better-than-expected 0.7 percent in the final three months of last year, official revised data showed Wednesday as the country prepares for Brexit.

For 2016 as a whole, however, the British economy grew by a lower-than-forecast 1.8 percent, the Office for National Statistics said in a statement.

Initial readings given last month by the ONS had put fourth-quarter gross domestic product growth at 0.6 percent and annual GDP at 2.0 percent.

"The second estimate of fourth quarter UK GDP was a bit of a mixed bag," noted Paul Hollingsworth, economist at Capital Economics research group.

"On the one hand, the figures confirmed that growth accelerated towards the end of last year, with the quarterly rise revised up... However, GDP growth for the year as a whole was revised down from 2.0 percent to 1.8 percent," due to a lower estimate for first-quarter GDP, he said.

Britain's economy has grown more strongly than expected since the country voted last June to exit the European Union.

Looking ahead, "lingering uncertainty about the UK's future relationship with the EU as negotiations get underway may hold back investment," Hollingsworth added in a note to clients.